Traditionally, a baker mixes pie crust dough by pressing a pastry cutter against the bottom of a mixing bowl to cut butter and shortening into flour and other dry ingredients. The resulting mixture should have roughly pea-sized lumps of fat distributed evenly throughout the dry ingredients. This is usually achieved by repeatedly rotating a parallel-bladed pastry cutter to different positions, pressing the cutter into the ingredients, then briefly stirring the mix. Hand-mixing cold butter into flour with a pastry cutter can be time-consuming and exhausting.
Optimum cutter blade spacing is crucial to obtaining a proper mix. A pastry cutter with blades that are too far apart leaves oversized, poorly distributed lumps. Blades that are too close together tend to clog and create lumps that are too small to produce a flaky crust. Wire cutters mix poorly and often fail to conform to the contours of a mixing bowl. Mixing machines equipped with standard mixing paddles or dough hooks do little more than push ingredients around a mixing bowl.
Some people avoid the difficulties of making pie crust by purchasing pre-made crusts from stores. However, most people prefer fresh pie crust made to a favorite recipe, no matter how tedious and difficult it is to create. A mixing machine attachment that effectively cuts butter and shortening into dry ingredients would ease and simplify creation of homemade pie crust.